The effects of invasive epibionts on crab-mussel communities: a theoretical approach to understand mussel population decline

TL;DR

This paper develops a mathematical model to understand how invasive epibionts affect crab-mussel communities, revealing impacts on mussel decline and predator-prey dynamics.

Contribution

It introduces a novel ODE model incorporating invasive epibionts and analyzes stability, bifurcations, and ecological outcomes using optimal control methods.

Findings

Model predicts conditions for mussel population decline.

Invasive epibionts alter predator-prey stability.

Results inform conservation strategies for mussels.

Abstract

Blue mussels (Mytilus edulis) are an important keystone species that have been declining in the Gulf of Maine. This could be attributed to a variety of complex factors such as indirect effects due to invasion by epibionts, which remains unexplored mathematically. Based on classical optimal foraging theory and anti-fouling defense mechanisms of mussels, we derive an ODE model for crab-mussel interactions in the presence of an invasive epibiont, Didemnum vexillum. The dynamical analysis leads to results on stability, global boundedness and bifurcations of the model. Next, via optimal control methods we predict various ecological outcomes. Our results have key implications for preserving mussel populations in the advent of invasion by non-native epibionts. In particular they help us understand the changing dynamics of local predator-prey communities, due to indirect effects that epibionts confer.